Cooling device for the oil systems of internal-combustion engines



Dans, 3Q, 1947. W. E. GREEN ET AL. 2,433451 COMBUSTION ENGINE S COOLING DEVICE FOR THE OIL SYSTEMS OF INTERNAL- Filed Dec. 10, 1943 4 Sheets-Sheet l DGC. 3 0, 194?. -W. EE AL 2,433,451

COOLING DEVICE FOR THE OIL SYSTEMS OF INTERNAL-COMBUSTION ENGINES Filed Dec. 10, 1943 Attorneys 7 D66. 30, W GREEN ET AL COOLING DEVICE FOR THE OIL SYSTEMS. OF INTERNAL-COMBUSTION ENGINES I Filed Dec 10', 1945 4 Sheets-Sheet 3 nvent Attorneys Dec. 30, 1947. w. E. GREEN ET AL 1 COOLING DEVICE FOR THE OIL SYSTEMS OF INTERNAL-COMBUSTION ENGINES Filed Dec 10, 1943 4 Sheets-Sheet 4 mwmwm x Q 1 w N m \m, W n4 N \W w w n H... .J. A

P atented Dec. 30, 1947 COOLING DEVICE FOR THE OIL SYSTEMS OF INTERNAL-COMBUSTION ENGINES William Ernest Green and William Frederick Forrest Martin-Hurst, Sunbury-on-Thames, England Application December 10, 1943, Serial No. 513,792 In Great Britain October 9, 1942 4 Claims. (01. 236-35) This invention relates to cooling apparatus applicable to the oil cooling system of an aircraft engine and has particular reference to cooling apparatus of the kind wherein the cooler is surrounded by a by-pass jacket or chamber through which the oil can be diverted and wherein the v flow of air through the main cooler is controlled by devices in the nature of adjustable shutters or louvres.

The object of the present invention is to provide an improved form of control device responsive to variations in oil pressure and temperature and which is designed more particularly to protect the cooler matrix from the shock pressure set up when starting from cold and to prevent oil being by-passecl when an increased pressure difference across the cooler is set up by partial obstruction of the matrix due to coring.

According to the invention the improved devices for controlling an oil cooler of the kind above described include means responsive to fluid pressure for opening the inlet to the by-pass jacket or chamber and for actuating means for closing or opening the shutters or louvres and a thermostatic device adapted to operate at a predetermined temperature to enable the pressure difference across the cooler to be utilised to control the position of the said louvres or shutters.

According to the preferred form of the invention, a device for controlling an oil cooler of the kind described includes a pressure operated valve device adapted to open an inlet for oil to flow through a by-pass jacket or chamber and to close the cooler shutters and a second valve device normally closing the passage to the cooler but adapted under thermostatic operation when the temperature of the oil increases to open the cooler outlet and close the by-pass passage irrespective of the position of the said pressure operated valve device.

Reference will now be made to the accompanylng drawings which illustrate byway of example a device constructed according to the invention and in which- Fig. 1 is a longitudinal sectional elevation showing the parts in an inoperative position,

Fig. 2 is an end view,

Fig. 3 is a sectional elevation similar to Fig. 1 but showing the pressure operated valve memher only open,

Fig. 4 is a sectional elevation showing the thermostatically operated valve only open and Fig. 5 is a sectional elevation showing both pressure and thermostatic valves in open operation. r

In the construction illustrated, the control device for an oil cooler of the kind above described comprises a casing l to which oil admitted through an inlet 2 under pressure from a pump, the inlet chamber 3 in the said casing communicating with a cylinder 4 in which is disposed a piston 5 which normally closes communication between the inlet chamber 3 and an outlet 6 which leads through a cylinder 1 and annular passage 8 to a port 9 communicating with a bypass passage, this position being shown in Fig. 1.

The inlet chamber 3 also communicates with one end of a cylinder 1 in which is mounted a sleeve valve I 0 which in the position shown in Fig. 1 closes communication between the said inlet chamber 3 and an annular port H connected to an outlet l2 communicating with the main cooler.

The piston 5 which controls the by-pass outlet is mounted upon a rod 13 which extends throughout the casing I and is carried in guide sleeves l4 and I5 at the ends thereof which permit the said rod to move axially when pressure is exerted upon the piston 5 as hereinafter described.

At one end the rod I3 is provided with coupling means I6 by which it is connected directly or indirectly to the cooler shutters and in the position shown in Fig. 1 which is the inoperative position of the device, the piston occupies a position wherein it cuts off communication completely between the inlet chamber 3 and the by-pass port 6 and is maintained in this position by the pressure of two springs. One of these is a preloaded spring H which bears against the inner face of the piston 5 and against an annular collar I8 fixed to the rod I3. Adjacent the annular collar 18 is a cup shaped collar l9 terminating in an annular flange 20 against which bears one end of a lightly loaded spring 2| whose opposite end bears against a fixed end component 22 of the cylinder 4.

The sleeve valve H] which controls the outlet I 2 to the cooler is also closed initially under spring action as shown in Fig. 1 and can only be opened by the operation of thermostatic devices disposed in the passage between inlet 2 and the chamber 3, said passage intersecting the cylinder 1. Preferably, two of these thermostatic devices 23 and 24 are employed, as shown, and they are of the wax filled or similar type which are insensitive, or substantially so to altitude and pressure changes, the thermostat 23 being arranged to operate under normal temperature increase, and the thermostat 24 being set to oper- 3 ate at the highest safe temperature in case the thermostat 23 should fail to operate.

The thermostats are mounted in the sleeve valve 10 their heads bearing in sockets formed at 25 within the body of the said valve and the piston rods 26 projecting at their opposite ends bearing against a fixed element ill adapted to close one end of the cylinder 1. The sleeve valve is formed with ports 32 which in the position shown in Fig. 1 allow free passage of liquid from the inlet 2 to the chamber 3.

At the end of the sleeve valve remote from the member 21, it is formed with a portion 28 of reduced diameter and terminates in a portion 29 of the same diameter as the main valve sleeve and against which bears one end of a spring 30 which also bears against an element 3i adapted to close one end of the cylinder 1.

The operation of the device above described is as follows:

In starting up from cold the pressure of the incoming oil cannot operate the sleeve valve l controlling the outlet to the cooler so that oil pressure built up in the inlet chamber 3 forces the piston 5 to move against the action of spring 2! towards the position in which the cooler shutters will be closed. The movement of the piston during that initial stage is transmitted through the collar I8 to the rod l3 whose movement is in turn transmitted to the shutters to close them and this movement continues until the maximum compression has been applied to spring 2i and the collar l9 abuts against the inner end of sleeve l5.

When this position is reached there is still no passage available to the oil in the chamber 3 so that the continued pressure moves the piston 5 still further towards the right thereby compress ing the pre-loaded spring I! until the passage 6 is uncovered and the oil can flow through the port 6 around the narrow portion 28 or the valve and through the annular passage 8 and port 9 to the by-pass passage. This position of the ports is shown in Fig. 3 and allows oil to'fiow from the pump through the valve casing and through the by-pass'jacket around the main cooler to the cooler outlet, the oil in the cooler being warmed during this operation.

As the temperature of the oil thus increases, a predetermined temperature is reached where the low temperature thermostat 23 expands and moves the sleeve valve I 0 towards the right to uncover the annular port H and thereby allow oil to flow through port l2 to the cooler, the parts under thermostatic control being then in the position shown in Fig. 4. This diversion of the oilto the cooler takes the pressure ofi piston 5 which gradually returns under the influence of Springs l1 and 2! towards the position shownin the upper part of Fig. 4 and in Fig. 1 and in doing so shuts off the passage 6 so that oil can-nolonger flowthrough the Icy-pass but through the cooler only whose shutters are opened owing to the return movement of the. piston 5.

As soon as the temperature of the oil has fallen sufliciently the thermostat 23 will contract and allow the spring 31] to restore the sleeve valve It! to a position in which it. closes the port I l leading to the cooler so that the piston valve 5 will again be moved by an increase of built up pressure in the inlet chamber 3 to closethe shutters and open the by-pass passage.

- A difficulty hitherto encountered in coolers especially when an aircraft is flying at high altitudes is that even when oil at a high temperature is flowing around tubes through which very cold air is passing, there is often a tendency for the oil to congeal on the tubes and form cores so that at maximum temperature conditions the pressure difference across the cooler will be such that the piston 5 will be operated and there will be a danger of the heated oil being directed to the bypass port. The device accordingto the present invention is designed to prevent this undesirable occurrence as the thermostatically operated sleeve valve ID will have moved under high temperature conditions acting. on the thermostat 23, in a direction to close the by-pass port 9 as shown in Fig. 5 and thus compel all the oil to pass through ports H and i2 to the cooler. The increased back pressure thereby set up will cause the piston valve member 5 to operate and close the shutters or flaps to prevent air entering the cooler until its matrix is cleared and normal conditions therein are restored.

In cases where it is desirable to control the flow of air through the cooler by means of a single large shutter on the outlet of the duct in which the cooler is mounted, the power required to operate this shutter is greater than can be provided by the control device above described. To meet such a case a hydraulic relay device may be operated by the by-pass valve Piston rod l3 so that the main hydraulic pressure available on the aircraft can be utilised to operate the shutter.

We claim:

1. A device for controlling the oil cooler of an oil circulating system having shutter means for controlling the flow of air through th cooler, and an oil by-pass for the cooler, comprising a piston and by-pass control valve responsive to the fluid pressure of oil circulating in the system and having means including a rod adapted to be connected to the shutter means and having a lost-motion connection with said piston for opening and closing the shutter means, a thermostatic device, said piston and by-pass valve being movable relatively to said thermostatic device, said thermostatic device being responsive to temperature of oil circulating in the system and operative at a predetermined temperature to control the fluid pressure acting on said piston, and means actuated by movement of said piston under the influence of fluid pressure thereon to first close the shutter means and to then open the by-pass control valve, including a pro-loaded spring interposed between said. piston and rod for actuating the latter during part of said movement and yieldable during another part of said movement to permit opening of the by-pass control valve.

2. A device for controlling the oil cooler of are oil circulating system having shutter means for controlling the flow of air through the cooler, and an oil by-pass for the cooler, comprising, a piston and by-pass control valve responsive to the fluid; pressure of oil circulating in the. system and having means including a rod, adapted to be connected to the shutter means and having said piston and by-pass control valve mounted for limited movement longitudinally thereof for opening and closing the shutter means, a thermostatic device, said piston and Joy-pass control valve being movable relatively to said thermostatic device, said thermostatic device being responsive to temperature of oil circulating in the system and operative at a predetermined temperature to control the fluid pressure acting on said piston, and means actuated by movement. of said piston under the influence of fluid pressure thereon to first close th shutter means and. to

then open the by-pass control valve, including a spring of sufiicient strength to transmit the first part of said movement to the shutter means to close the same but yieldable during a further part of said movement to permit opening of the bypass control valve.

3. A device for controlling the oil cooler of an oil circulating system having shutter means for controlling the flow of air through the cooler, and an oil by-pass for the cooler, comprising a piston and by-pass control valve responsive to the fluid pressure of oil circulating in the system and having a lost-motion connection with the shutter means for opening and closing the latter, a thermostatic device, said piston and by-pass control valve being movable relatively to said thermo static device, said thermostatic device being responsive to temperature of oil circulating in the system and operative at a predetermined temperature to control the fluid pressure acting on said piston, and means actuated by movement of said piston under the influence of fluid pressure thereon to first close the shutter means and to then open the by-pass control valve, including a lightly-loaded spring which is yieldable during a preliminary part of said movement to permit closing of the shutter means, and a second preloaded spring which is yieldable during a further part of said movement to permit opening of said by-pass control valve.

4. A device for controlling the oil cooler of an oil circulating system having shutter means for controlling air flow through the cooler, and an oil by-pass, comprising a thermostatically controlled valve device, a pressure-operated valve device movable relatively to the thermostatically controlled valve device and having means for connecting the pressure-operated valve device to the shutter means and operative to open the inlet to the by-pass and to close the shutter means, and a valve device including a valve sleeve having a passage therein through which oil flows to said pressure-operated valve device, and movable axially to control the oil inlets to the cooler and the by-p-ass, a thermostat within said valve sleeve responsive to a normal increase in temperature of the circulating oil for moving said sleeve in a direction to open the oil inlet to the cooler and close the oil inlet to the by-pass, a spring against which said sleeve is movable by said thermostat and operative to restore said sleeve to a position toclose the oil inlet to the cooler and open the oil inlet to the by-pass under control of said thermostat in response to a drop in temperature of the circulating oil, and a second thermostat responsive to a relatively higher oil temperature than that to which the first-mentioned thermostat is responsive for operating said sleeve in the event of failure of the first-mentioned thermostat.

WILLIAM ERNEST GREEN.

WILLIAM FREDERICK FORREST MARTIN-HURST.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,635,083 Hermesmeyer July 5, 1927 2,107,188 Ryder Feb. 1, 1938 2,136,235 e Crago Nov. 8, 1938 2,291,607 Chausson Aug. 4, 1942 2,353,610 Chisholm July 11, 1944 2,359,533 Shogran Oct. 3, 1944 FOREIGN PATENTS Number Country Date 232,309 Great Britain Apr. 14, 1925' 305,052 Germany Oct. 18, 1919 350,065 Italy July 5, 1937' 463,313 Great Britain Mar. 19, 1937 522,740 Great Britain June 26, 1940 546,452 Great Britain July 14, 1942 547,350 Great Britain Aug. 24, 1942; 662,977 Germany July 26, 1938 

